Implementation of a new and precise objective test for strabismic amblyopia is proposed that may allow much earlier diagnosis of the condition than is at present possible and on a mass screening basis. Based on stereopsis, the test allows quantitative diagnosis of the condition in preschool children and infants. Results are obtained by eye movement analysis. Longitudinal and cross-sectional data will be collected on: (a) normal monocular visual acuity and stereoacuity development at these ages, and (b) course of amblyopia development. Implications of the stereotest for strabismic amblyopia pathogenesis theory is considered, especially as to its possible binocular nature and the possible early role of "microstrabismus" or "microtropia."